The CMYK stands for the four primary colors that are generally used in photographic and printing processes: Cyan, Magenta, Yellow and Black. Combining these colors creates the impression of the image on prints. Contrary to what most online printing companies claim, there is only 99% guarantee that the colors of the printed images will be the exact replication of those that appear on-screen. This is due to the RGB (Red, Green Blue) display color system that is generally used for PC monitors.
Original source at Banners and brochure

Things to Consider in Making Business Brochures The use of brochures in advertising and promotion has been a staple part of the industry. Over the decades, brochure use in advertising has been vital especially in the past when the technologically advanced forms of advertising and promotion were not invented yet.
Original source at Flyer Printing